Native Delaware: Seasonal Symphony of Frog Calls Returns

April 19, 2013 under CANR News

On April nights, Holly Niederriter can be found driving slowly down the back roads of New Castle County. Although she appears to be meandering, her excursions are quite purposeful.  A wildlife biologist with the Delaware Department of Natural Resources and Environmental Control, Niederriter is listening for frog calls.

She is one of dozens of Delawareans who drive around after dark searching for frogs as part of the Delaware Amphibian Monitoring Program. The first survey period kicked off in late February, the second starts in a few days, and the final survey occurs in June. Participants are volunteers from the community; most don’t have Niederriter’s wildlife savvy. But they all receive training, and before their debut, take an online quiz to ensure they can distinguish the calls of Delaware’s 16 species of frogs.

American toad by Jim White“Frog calls are an important way to determine where different species occur and how populations are doing over time,” says Niederriter.  “Because most amphibians need both aquatic and upland habitats, they can serve as important indicators of water quality and other aspects of environmental health.”

A colder-than-average early spring made for a slow start to the frog-calling season.  Early April is often the peak of spring peeper season, when the sleigh-bell-like chorus of these tiny frogs reaches maximum volume in vernal pools and marshes. But the beginning of this month was so chilly that the peepers didn’t want to peep.

“Male peepers call to attract a mate but if the weather isn’t warm enough they hunker down and wait it out,” says Jim White, associate director for land and biodiversity management at the Delaware Nature Society and an adjunct herpetology instructor at the University of Delaware. “I didn’t hear a single peeper during the first few days and nights of April.”

Now that temperatures are more seasonal, the spring peepers are out in full force. Recently, they’ve been joined by the pickerel frog, with its snore-like call, and the American toad, which boasts a musical trill. In the Coastal Plain region (Kent and Sussex, plus a sliver of New Castle County), you also can enjoy the throaty croak of the Southern leopard frog.

You need a sharp ear to recognize the call of the American toad, notes Jake Bowman, a UD professor of entomology and wildlife ecology.

“American toads are frequently heard all over our area but rarely do people realize what they are hearing,” he says. “Unlike the commonly recognized sleigh bell call of the spring peeper, the American toad has a high pitched trill. Here on the UD campus, you can find them in most of the wetlands on our farm.”

A father of two sons, Lee, 10 and Ethan, 5, Bowman likes the fact that frogs are “kid-friendly.”

“Probably the nicest thing about toads is that it’s often the only amphibian kids have a chance to handle. My boys love the chance to chase and capture American toads and learn more about them,” he says. “After the boys have checked out the toads, we release them back where we found them.”

Like the Bowman boys, James White, Jr. grew up playing with frogs with his father, Jim White. Now a UD freshman, White is majoring in wildlife conservation and hopes to become a national park ranger.

“For as long as I can remember, I went looking and listening for frogs every rainy, spring night,” says White. “We had a marsh only a few yards from our house so it was never difficult to hear them.”

“I will go herping with my father but because of college it probably won’t be until school is out,” he says. “My favorite frog of spring is the pickerel frog. I always found them pretty frogs and very jumpy, making them a challenge to catch.”

If you want to catch frogs with your kids (or at least see and hear them), Bowman has a few suggestions. Look for terrestrial species on the ground in woodlands and other land habitats. Semi-aquatic species can be seen on the shoreline or surface of freshwater habitats. To find breeding frogs, head to vernal pools and marshes. Warm, rainy nights make for the very best frog-watching. Pack a bright flashlight and plenty of patience.

A spring peeper, for example, is only about an inch long and its brown, gray and green colors don’t stand out, especially at night. “You can practically be on top of them and still not see them,” notes Bowman.

But it’s worth the wait to see a peeper, especially a male one. Males have large vocal sacs under their chins that they pump full of air until they look like balloons about to burst, When they peep, the air is discharged and the shiny sac deflates.

How to Help

To learn more about volunteering with the Delaware Amphibian Monitoring Program, contact Vickie Henderson at 735-8651 or vickie.henderson@state.de.us

Article by Margo McDonough

Photo by Jim White

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UD researcher works to ensure Delaware’s wild turkey population proliferates

December 13, 2012 under CANR News

Wild turkeyIn colonial times, the Eastern wild turkey was abundant in Delaware. But by the late 1800s, wild turkeys were gone, eradicated by over-zealous market hunters and habitat destruction.

Usually, that’s the end of the story for a species.

Sometimes, however, species can be re-introduced to their original habitats. Such has been the case with the Eastern wild turkey, one of Delaware’s greatest conservation success stories, says Matt DiBona, a wildlife biologist with the Division of Fish and Wildlife in the state’s Department of Natural Resources and Environmental Control (DNREC).

In 1984, 34 Eastern wild turkeys from Pennsylvania, New Jersey and Vermont were given new homes in the woodlands of Sussex. In the 1990s, 100 wild turkeys from New York were released; in 2002 they were joined by another 33 birds from South Carolina and Virginia.

Throughout this period, turkeys in Sussex were captured and released further north to ensure distribution statewide.

This starter stock of 167 birds and their descendants have been prolific. “Today, Delaware’s wild turkey population is established and continues to spread,” says DiBona. “The population established so quickly that seven years after re-introduction we were able to offer a limited hunting season. We’ve continued to hold an annual four-week spring hunting season for gobblers.”

However, the Eastern wild turkey’s re-introduction to Delaware hasn’t been an unequivocal success story. About 20 years ago there was a population decline. It wasn’t widespread and numbers picked up after that. But Division of Fish and Wildlife officials realized the agency needs to better understand the population dynamics of wild turkeys.

Three years ago, the Division of Fish and Wildlife teamed up with Jake Bowman, a University of Delaware associate professor of wildlife ecology, to get a better handle on potential limiting factors affecting turkey production. “This is especially important because the number of turkey hunters is continuing to increase each year,” notes DiBona. “We thought it prudent to do research on these birds now to help provide some context for our harvest data.”

“The research project focused on hen reproduction, including the number of eggs laid and the survival rate of the poults (the babies), to determine reasons for population decrease,” says Bowman.

But you can’t figure out how many eggs a particular hen laid if you can’t distinguish her from the other hens – or find her, for that matter. That’s where turkey backpacks come into the story.

Seventy-six hens at Redden State Forest, near Georgetown, were equipped with little backpack transmitters. The transmitter, which is fastened under the hen’s wings with elastic cords, produces a radio frequency that can be detected up to a mile away.

During breeding season, Bowman’s grad students were at the state forest every day and at least several times a week other times of the year. Although Bowman’s teaching responsibilities kept him busy, at least once a week he participated in the fieldwork.

“You’re out there at all hours of the day and night, when it’s raining, when it’s hot,” he says. “But it’s great. I find research into native species such as the wild turkey more rewarding than study abroad trips I lead to places like Tanzania and Cambodia. There you’re just observing. But with research like this, you’re the one trying to find the answers.”

And Bowman and his team have found some of those answers. They’ve discovered that hens that nested on private land hatched more nests than those on public land, probably because of a difference in vegetation. They discovered that the average number of eggs per nest was eight, compared to the 10-14 eggs per nest seen in other states. Nesting success rates in Delaware are low compared to nearby states. In 2011 just 19 percent of the nests resulted in poults. The research team also discovered that fox and owl predation is a big problem, not only for the poults but for the mother hens.

There is good news to report, too. “Poult survival is greater in Delaware compared to other states, allowing for new birds to be recruited into the population,” says Bowman.

Although Bowman is wrapping up his project, the Division of Fish and Wildlife continues to track data in a variety of ways, including its seasonal Wild Turkey Survey.

“This is a citizen-scientist project; you don’t need to be a wildlife biologist to contribute,” says DiBona. “If you see wild turkeys on your drive to work or when you’re walking on a Sunday afternoon, we want to know about it.”

For example, Jason Beale, manager of Abbott’s Mill Nature Center, reported that he saw an adult hen with seven poults on Aug. 8. He’s participated in the survey for the past two years.

“I’ve lived in Delaware since 2006. I know that in 2011 and 2012 I saw more wild turkeys than in all the other years combined,” says Beale. “We see them in Lee Meadow here at Abbott’s Mill. Isaacs-Green Preserve is another good spot to see them.”

“Even when you don’t see them, you know they’re here,” adds Beale. “At overnight camps we can hear them gobble at dawn and dusk and we routinely see turkey tracks on the trails.”

How to help

To participate in the 2013 Wild Turkey Survey, contact Matt DiBona at 735-3600 or matthew.dibona@state.de.us.

Article by Margo McDonough

Photo by Bob Eriksen

This article can also be viewed on UDaily.

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CANR Summer Institute offers glimpse of graduate student life

July 20, 2010 under CANR News

This summer five undergraduate students are conducting research with faculty mentors in the University of Delaware College of Agriculture and Natural Resources (CANR), experiencing the challenges and rewards of what a graduate education at UD might be like.

As participants in the Summer Institute in the Agricultural and Natural Resources Sciences, hosted by the college, these students are taking part in ongoing research projects guided by personal faculty mentors, networking with current graduate students and other staff within CANR, and interacting with industry professionals.

“The Summer Institute is a team effort by faculty from all departments in our college,” said Tom Sims, deputy dean of the college. “It provides these five outstanding undergraduate students the opportunity to conduct hands-on research and learn about the range of graduate education opportunities available in the agricultural and natural resources sciences.”

Now in its second year, the 10-week program — funded by the college and a Graduate Innovation and Improvement Grant from UD’s Office of Graduate and Professional Education – draws students from under-represented populations who are interested in a graduate degree in agriculture and natural resource sciences.

Maria Pautler, the program’s coordinator, said the Summer Institute was expanded from 4 to 10 weeks after last year’s participants suggested a longer program. The extended program allows students to become more involved with their research projects and present their findings at a campus-wide symposium at the end of the summer, she said.

“This, coupled with opportunities to attend seminars, workshops, and panelist luncheons, is exposing the students to facts and opinions on preparation for, and life in and beyond, graduate school,” Paulter said.

The 2010 CANR Summer Institute participants are:

Kamedra McNeil, of Forestville, Md., is a molecular biology major at Winston-Salem State University in North Carolina. McNeil is involved in the Winston-Salem Student Government Association, Tri-Beta Biological Honors Society, NSCS Scholars and Pre-Marc Scholars. She is interested in a career in forensic biology. During her time at the Summer Institute, McNeil is studying different genes associated with photoperiod in plants. Her faculty mentor is Randall Wisser, assistant professor of plant and soil sciences.

Shurnevia Strickland, of Philadelphia, is a senior applied animal science major at UD. Strickland is secretary and webmaster for Minorities in Agriculture, Natural Resources and Related Sciences (MANRRS). She is interested in future research with genetics. At the Summer Institute, Strickland is studying the endothelin 3 gene in the silkie chicken. Her faculty mentor is Carl Schmidt, associate professor of animal and food sciences.

Rochelle Day, of Laurel, Del., is a senior pre-veterinary medicine and animal biosciences major at UD. Day is a member of Puppy Raisers of UD (PROUD) and MANRRS, and is looking toward a career in animal pathology. At the Summer Institute, Day is mapping the genome of the Infectious Laryngotracheitis Virus (ILTV), an upper respiratory disease in birds that causes economic losses for the poultry industry. Her faculty mentor is Calvin Keeler, professor of animal and food sciences.

Rothman Reyes, of Long Island, N.Y., is a sophomore pre-veterinary medicine and animal biosciences major at UD with minors in sexuality and gender studies, and women’s studies. Reyes raises puppies for Guiding Eyes for the Blind and is a member of the LEARN mentor program. He also serves as co-president of the PROUD special interest community. Reyes hopes to practice veterinary medicine at a zoo. At the Summer Institute, Reyes is creating a fosmid library, where he will induce a mutation onto the Infectious Laryngotracheitis Virus (ILTV) to create a vaccine. His faculty mentor is also Calvin Keeler.

Kristina Barr, of Kingstree, SC., is a senior biology major at Benedict College in Columbia, S.C. She is a member of the Environmental Awareness Club at her school and plans to pursue a career as an ecologist. Her research at the Summer Institute involves the effects of rose bushes on birds’ ability to forage for food. Her faculty mentors are Jacob Bowman, associate professor, and Greg Shriver, assistant professor, both of entomology and wildlife ecology.

Article by Chelsea Caltuna

Read the article on UDaily by clicking here.

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Center for Managed Ecosystems puts past urban forest research into new FRAME

June 8, 2010 under CANR News

Greg Shriver, assistant professor of wildlife ecology in the Department of Entomology and Wildlife Ecology and research scientist with the Center for Managed Ecosystems at the University of Delaware, is collaborating with the U.S. Forest Service to continue work on a project that focuses on assessing the conditions of urban forests and explores ways in which to improve those conditions.

The project is known as Forest Fragments in Managed Ecosystems, or FRAME, and it has its origins in a study titled “Wildlife Ecology and Urban Impact” conducted 45 years ago at UD by scientists in the Department of Entomology and Wildlife Ecology and the Forest Service.

The 1965 study was continued by Roland Roth, UD professor emeritus of wildlife ecology, beginning in 1972. Although Roth could not have known at the time, Shriver said that his work — conducted on the UD Farm — became the longest running study on the demographics of the wood thrush, a neotropical migratory bird.

Shriver, who subsequently picked up the mantle, called the wood thrush the “hallmark species” for this research and said FRAME builds on Roth’s earlier studies. The FRAME project was initiated as a collaborative effort between Shriver; Vincent D’Amico, a Forest Service scientist stationed at UD; Jake Bowman, associate professor of entomology and wildlife ecology; and Jeff Buler, assistant professor of entomology and wildlife ecology.

Shriver said FRAME is “a fairly large-scale forest fragmentation study aimed at assessing the condition of urban forest fragments to see if we can increase their quality.”

These forest patches dotting the developed landscape “are providing the some of the only remaining habitat for neotropical migratory birds, small mammals, and insects,” he said.

The group is currently establishing long-term plots and surveying the condition of Mid-Atlantic forest fragments.

After assessing the overall health of the forest fragments, Shriver said he and his colleagues will research ways to improve them. “The big picture is that these fragments are providing important ecosystem services — air, water, things required to make the area livable,” he said. “The goal of the FRAME project is to better understand the interactions between soil, water, plants and the animals dependent on them within urban and suburban environments.”

Shriver, who will be aided by graduate students, said the study will be multifaceted, with the first part focusing on multitrophic effects of soil acidification and biodiversity.

“There has been some concern that acidification in soils, especially here in the Northeast, could be limiting the availability of calcium-rich prey — such as snails and isopods — that birds need during the breeding season to make eggshells and feed their nestlings, because the nestlings’ growth rate is so fast and they need so much calcium,” Shriver said. “Studies have shown that if you have limited calcium availability, you have limited calcium-rich prey, which then limits the breeding density and reproductive success of some bird species.”

The FRAME study has broken the Newark area’s urban forest fragments into grids using GPS systems, starting with the original study patch from the Roth study and adding 19 other woodlots.

In each of the fragments, Shriver said he and his students plan to “estimate breeding bird territory density, nest survival, a measure of reproductive success, and species diversity. We’re also taking soil samples and then litter samples to see if we can link the soil pH to calcium-rich prey.”

Shriver explained that a low pH means that the soil has a high amount of acidification, and that “the acidification comes mostly from acid rain, which has been greatly reduced since the height of the Industrial Revolution, but the soils have likely not recovered. Once you push a soil into an acidic state, unless it has some buffering capacity, it is very hard to get it back.”

What happens with soil that has been pushed to an acidic state, he said, is a reduction in calcium-rich prey, which in turn limits food for breeding birds. The birds either have lowered reproductive success or leave that forest fragment.

The first two years of the FRAME study are dedicated to gathering the pre-data, showing the present condition of the soil. Shriver said the research team then plans to “lime the forest patches to see if we can increase their quality, which will raise the pH and release the calcium,” thereby improving biodiversity.

They plan to treat 10 sites with lime and leave another 10 sites untreated in order to compare differences in soil quality. He said he is confident that “changing the pH is going to change a lot to these forest fragments.”

The research team is partnering with the Newark Department of Parks and Recreation, New Castle County Parks, and Delaware State Parks. Shriver said that “without the cooperation and enthusiasm we’ve received from all the partners, this project would not be possible.”

Shriver received a bachelor of science degree in wildlife management from the University of Maine, a master’s degree in wildlife conservation from the University of Massachusetts and a doctorate in environmental forest biology from the State University of New York (SUNY). He joined the UD faculty in 2005.

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